This is a competitive renewal application to continue our participation as a member of the Neonatal Research Network. The Women and Infants? Hospital/Brown University site has been a member of the Network during the past 2 cycles (completing year 10 in April, 2001 ). The application has detailed the productivity of this center during the past five years. We have also documented the productivity of our centers in other non-Network clinical and basic science research activities. Included in the application is a proposed protocol for submission to the Steering Committee for consideration. This protocol is entitled: "Randomized Control Trial of Combined Sodium Restriction and Moderately Early Corticosteroid Treatment to Reduce the Incidence of Chronic Lung Disease in Extremely Low Birth Weight Infants. This is a 2 x 2 factorial design intention to treat trial that will test the hypothesis that sodium restriction in the first week of life will allow for a negative sodium balance, ensure physiologic contraction of extracellular body fluid, improves pulmonary function, less need for assisted ventilation and less risk for CLD. The other hypothesis is that moderately early use of CS will also reduce the incidence of CLD without significant serious side effects. The additional hypothesis is that a combination of the two interventions will have an "add-on" effect in reducing the incidence of CLD. Success of this application will allow us to participate in a Network that will achieve the vision of NICHD in promoting collaborative clinical research to derive new knowledge to improve the quality of care for high- risk infants.